A 2019 FDA-funded study found that common chemical UV filters showed up in the bloodstream with levels well above the FDA's own safety threshold after only a single day of use. There hasn’t been long term studies on its effects on the human body and for more than a decade, you have been the test.
Sunscreen (chemical filters) absorbs into your skin and works by converting UV rays into heat, and is how it ends up in your blood. Sunblock (mineral filters like zinc oxide) sits on top of your skin and physically deflects UV rays before they get in. One becomes part of you. The other doesn't.
Zinc oxide is broad spectrum protection, blocking both UVB and UVA rays. It's what most sunscreens are built to stop, UVA is the ray you don't feel. It penetrates deeper, breaks down collagen, speeds premature aging, and has long-term skin cancer risk. Most chemical sunscreens need two or three different filters to cover both ranges. Zinc oxide covers both. All on its own, sitting on top of your skin and reflecting the rays before they get in at all.
It's why we only use non-nano zinc oxide. It doesn't absorb into your body and stays on the surface of your skin where it can actually do its job. Nano zinc is small enough to disappear into your body, which is what you don't want from a barrier. Non-nano stays a physical shield, not fine dust that slowly dissipates.
That same size difference is why it doesn't wash off you and settle into reef systems the way nano-sized chemical filters do. Hawaii and Key West banned oxybenzone and octinoxate after both chemicals were documented to cause coral bleaching and disrupt marine life, even in trace amounts, which means every beach day is a bad day for the ocean.
Zinc oxide isn't a new option. It was always the standard, before chemistry found a cheaper alternative. You shouldn’t have to choose between protecting your skin and protecting the water you're swimming in. Our tallow based sunblock maintains that standard, without asking your body to absorb something nobody's finished studying
Try it once and you'll feel the difference the first time you towel off.